Question about parralell wires and magnetic fields. Help?

Question

If a wire is hooked up to an Electro Motive Force (EMF) and produces a magnetic field, would it produce the same magnetic field strength if another identical wire was hooked up to the EMF in parralell? Or would the magnetic field be stronger or weaker?

Answer 1

The magnetic fields from the wires will add linearly. The magnetic field from each wire depends on the current flowing through that wire. The current in turn depends on the the applied EMF (V) and the wire's resistance (R). I = V/R. If the wires are cinnected in parallel, the will have the same EMF applied. Therefore both wires will carry its own current as determined by its own resistance, and is independent of the current in the other wire (this assumes that the source of the EMF is not current-limited).

Whether the fields increase or decrease depends on the geometrical arrangement of the wires. If the wires are also physically parallel to each other, the addition of the second wire will increase the resulting magnetic field at all points outside the wires, but decrease the field between the wires. The field lines circle the wires, and if the currents are in the same direction, the direction of the magnetic field around each wire (as determined by the "right hand rule") is the same. Between the wires, the field from one wire is down, and the field from the other is up, so they tend to cancel, weakening the field. Outside the wires, the fields are in the same direction, so they add and the fields there are stronger.

Answer 2

The magnetic field strength induced by a current in a straight wire conductor is given by B = [(permeability of medium)X(current)]/[(4pi)x(radius away from the wire)]
Hence, magnitude of magnetic field strength is directly proportional to the magnitude of the current flowing through the conductor. Connecting a wire in parallel will mean less current flowing through each branch. Hence, magnetic field strength will decrease for each wire if you consider them separately.

Answer 3

Yes there will be mutual force. To know whether these forces are attractive or repulsive we must know the direction of the currents. Their strengh alsodepends upon the magnitude of the currents